[CentOS] CPU usage from top

Fri Dec 9 16:52:43 UTC 2005
William Warren <hescominsoon at emmanuelcomputerconsulting.com>

94.2% id

that's 94 percent idle.  Looks good here and your load averages are low 
as well.  Where's the problem?


Bowie Bailey wrote:
> I'm seeing some strange results from top on CentOS 4.0.  When it first
> starts, it reports low CPU usage.  The next refresh (and subsequent)
> refreshes, it shows high CPU usage.  In both cases, there is nothing
> shown in the process list that is using much CPU.  What is causing
> this?
> 
> Here is some truncated output from a single run of "top -b -n 2":
> 
> ----------------------------------------------------------------------------
> --
> top - 10:22:02 up 34 days, 14:36,  2 users,  load average: 0.98, 0.56, 0.51
> Tasks: 116 total,   1 running, 115 sleeping,   0 stopped,   0 zombie
> Cpu(s):  3.7% us,  0.7% sy,  0.0% ni, 94.2% id,  1.3% wa,  0.0% hi,  0.0% si
> Mem:   1034676k total,   610804k used,   423872k free,    35796k buffers
> Swap:  1052248k total,    14220k used,  1038028k free,   314524k cached
> 
>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> 16412 root      16   0  2280  864  664 R  5.6  0.1   0:00.06 top
>     1 root      16   0  3148  516  464 S  0.0  0.0   0:01.91 init
>     2 root      RT   0     0    0    0 S  0.0  0.0   0:04.32 migration/0
>     3 root      34  19     0    0    0 S  0.0  0.0   0:00.34 ksoftirqd/0
>     4 root      RT   0     0    0    0 S  0.0  0.0   0:02.32 migration/1
>     5 root      34  19     0    0    0 S  0.0  0.0   0:00.39 ksoftirqd/1
>     6 root       5 -10     0    0    0 S  0.0  0.0   0:00.13 events/0
>     7 root       5 -10     0    0    0 S  0.0  0.0   0:00.00 events/1
>     8 root       5 -10     0    0    0 S  0.0  0.0   0:00.18 khelper
>     9 root       5 -10     0    0    0 S  0.0  0.0   0:00.00 kblockd/0
> 
> 
> top - 10:22:05 up 34 days, 14:36,  2 users,  load average: 0.98, 0.56, 0.51
> Tasks: 116 total,   1 running, 115 sleeping,   0 stopped,   0 zombie
> Cpu(s): 49.1% us,  1.6% sy,  0.0% ni, 48.8% id,  0.2% wa,  0.2% hi,  0.2% si
> Mem:   1034676k total,   610804k used,   423872k free,    35800k buffers
> Swap:  1052248k total,    14220k used,  1038028k free,   314520k cached
> 
>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> 16412 root      17   0  2288  960  748 R  1.6  0.1   0:00.11 top
> 16052 bowieb    16   0  8288 2232 1812 S  0.3  0.2   0:03.04 sshd
>     1 root      16   0  3148  516  464 S  0.0  0.0   0:01.91 init
>     2 root      RT   0     0    0    0 S  0.0  0.0   0:04.32 migration/0
>     3 root      34  19     0    0    0 S  0.0  0.0   0:00.34 ksoftirqd/0
>     4 root      RT   0     0    0    0 S  0.0  0.0   0:02.32 migration/1
>     5 root      34  19     0    0    0 S  0.0  0.0   0:00.39 ksoftirqd/1
>     6 root       5 -10     0    0    0 S  0.0  0.0   0:00.13 events/0
>     7 root       5 -10     0    0    0 S  0.0  0.0   0:00.00 events/1
>     8 root       5 -10     0    0    0 S  0.0  0.0   0:00.18 khelper
>     9 root       5 -10     0    0    0 S  0.0  0.0   0:00.00 kblockd/0
> ----------------------------------------------------------------------------
> --
> 
> Notice 3.7% usage on the first one and 49.1% usage on the second.
> 
> I suspect that top isn't showing me everything.  I know that some
> versions of top had problems with showing proper CPU usage for
> threaded applications.  Is that still a problem with the current
> version of top?
> 
> Bowie
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> http://lists.centos.org/mailman/listinfo/centos
> 

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every tongue that shall rise against thee in judgment thou shalt 
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